Plug in automation failure (PT LE&Digi001)

[mnstudio]

I put a Limiter plug on Master track switching it between BYPASS ON & BYPASS OFF by automation and all seem to work fine, except for the matter that the plug ALWAYS WORKS (also when automation put it on BYPASS OFF mode, and the relevant insert button of Master track becomes grey). Note that Master track is on read mode.
The strange is that with automation off all works fine: I can regularly switch between BYPASS ON & OFF and the plug WORKS or NOT. Any idea?
Fulvio

[kimbe]

You can try to re-install your ProTools, but remember to take care of your plug-ins preferences which are in DAE folder .